HJ Series Bit Diameter（Inch）

Thread（API REG）

5 7/8″、6″、6 1/2″、6 3/4″

3 1/2″

7 7/8″、*1/2″、*3/4″

4 1/2″

9 1/2″、*5/8″、*7/8″、*2 1/4″

*2 1/2″、*3 1/8″、*3 5/8″

6 5/8″

*6″、*7 1/2″

7 5/8″

IADC CODE

Applicable Formations

Recommended Drilling Parameters

WOB (kn/mm)

（bit dia）

Speed r/mm

**7

soft formation with low compressive strength and high drillability，such as softshale、clay、salt,etc

0.***0.*0

**0~*0

**7

soft formation with low compressive strength and high drillability，such as softshale、clay、salt,soft limestone,etc

0.***0.*0

**0~*0

**7

soft to medium soft formation or a hard interlayer with low compressive strength,such as anhydrite、soft limestone、sandstone,etc

0.*5~0.*0

**0~*0

**7、**7

medium hard formation ,thick hard interlayer with High compressive strength,such as Hard shale、Limestone、sandstone、dolostone,etc

0.*5~1.*5

**0~*0

**7、**7

soft formation with low compressive strength and high drillability，such as softshale、clay、salt,soft limestone ,etc

0.*5~1.*0

**0~*0

**7、**7、**5

soft formation with low compressive strength and high drillability，such as shale、clay、sandstone,limestone ,etc

0.*0~0.*0

**0~*0

**7、**7

medium soft formation、hard abrasive layers with Low compressive strength,such as hard Shale, anhdrite, Soft limestone, sandstone, Laminated dolostone etc.

0.*5~0.*0

**0~*0

**7、**7

medium hard and hard abrasive formation with high compressive strength,such as limestone、dolostone、sandstone,firestone,etc

0.*0~1.*0

**0~*0

**7

Hard abrasive formation，such as limestone,dolostion,firestone,hard sandstone,etc

0.*0~1.*0

**0~*0